Articles
  • Structural and electrical properties of K(Ta,Nb)O3 thin film prepared by sol-gel method for electrocaloric devices

  • Min-Su Kwona, Ji-Won Kima, Joo-Seok Parkb and Sung-Gap Leea,*

  • aDept. of Materials Engineering and Convergence Technology, RIGET, Gyeongsang National University, Jinju 52828, Korea
    bBusiness Cooperation Center, Korea Institute of Ceramic Engineering and Technology, Jinju 52851, Korea

Abstract

This study investigated the structural and electrical properties of thin K(Ta0.6Nb0.4)O3 films for their applicability to electrocaloric devices. Both of the sol-gel and spin coating methods were used to fabricate thin films. Those sintered at 650 oC showed a KTN phase with pyrochlore of K2Ta2O6, but those sintered at 750 oC showed pure polycrystalline phase without a pyrochlore phase. The lattice constants observed were a= 3.990nm. The dielectric constant rapidly decreased due to decrease in polarization of space charge approximately at an applied frequency of 10 kHz. The dielectric constant and loss at 30 oC of the thin films sintered at 750 oC were 3,617 and 0.264. The dielectric constant of the specimen sintered at 750 oC decreased to about -8.27 %/V according to the applied DC field. The remanent polarization and coercive field at 36 oC of the specimen sintered at 750 oC were 20.0 μC/cm2 and 122.6 kV/cm. When the electric field of 247 kV/cm was applied to the specimen sintered at 750 oC, the highest electrocaloric property of 3.02 oC was obtained.


Keywords: K(Ta,Nb)O3 thin films, Ferroelectric, Electro-caloric effect, Sol-gel method

This Article

  • 2020; 21(6): 725-730

    Published on Dec 31, 2020

  • 10.36410/jcpr.2020.21.6.725
  • Received on Jun 12, 2020
  • Revised on Sep 3, 2020
  • Accepted on Oct 6, 2020

Correspondence to

  • Sung-Gap Lee

  • Dept. of Materials Engineering and Convergence Technology, RIGET, Gyeongsang National University, Jinju 52828, Korea
    Tel : +82-55-772-1687 Fax: +82-55-772-1689

  • E-mail: lsgap@gnu.ac.kr